Electronic device including electronic component, heat dissipating member and alloy layer

ABSTRACT

A method for manufacturing an electronic component device in which an electronic component and a heat dissipating member are connected by a heat conducting member, the method comprising forming one of a plate shape metallic member and a recessed metallic member on the electronic component by a selected one of vapor deposition processing and plating processing, forming the other of the plate shape metallic member and the recessed metallic member on the heat dissipating member by a selected one of vapor deposition processing and plating processing, and filling a liquid metal in the recessed part of the recessed metallic member thereby to form the liquid metal, the plate shape metallic member, and a part of the recessed metallic member into a solid solution.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuing application, filed under 35 U.S.C.§111(a), of International Application PCT/JP2003/02006, filed Feb. 24,2003.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to an electronic component andheat dissipating member, and a method for semiconductor manufacturingthrough the use of them. More particularly, the invention relates to aheat conducting member which connects an electronic component and a heatdissipating member.

2. Description of the Related Art

In these years, information processing units are demanded to providehigher functions and higher performances. To realize the units havingthese characteristics, the electronic components used in the units alsohave improved in their functions and processing-speed.

However, since the resultant improvement increases heat generated in theelectronic components, the heat generated has been liable to causeerroneous operations in and lower performance of the units. Accordingly,effective heat-dissipating and cooling the electronic component aredemanded.

One of the generally used cooling technologies is that in which the heatgenerated in the electronic component is radiated into the air throughconducting the heat to a heat sink tightly connected to the electroniccomponent. However, in the technology, the poor degree of contactbetween the electronic component and the heat sink results in lowthermal conduction.

A method of one improving the defect of prescribing technology isdisclosed in the unexamined published application Tokkai 2002-30217 inwhich an effective heat conduction is provided by increasing the thermalconnection between the electronic component and the heat sink withtightly connecting each other by thermal conductive resin includingfiller for thermal conduction.

Another cooling technology is disclosed the unexamined publishedapplication Tokkai-Sho 63-102345. The cooling technology disclosed inthe publication is related to the improvement of heat conduction withconnecting tightly an electronic component and a heat radiating memberfor increasing the thermal transfer from the component to the heatradiating member through a heat conductive alloy. The heat conductivealloy is a metal in the coagulation state of indium as metal and galliumas liquid metal.

Further the patent application 2002-140316 discloses a method forcooling which adopts a method for improving a heat transferring ratiobetween electronic component and a heat radiating member in the way ofconnecting the component and the member with a thermal conducting alloymade of metal indium and liquid metal. The thermal conducting alloy issurrounded by a bank for preventing spillover of the alloy since thealloy is liquid.

However the disclosed technology in the unexamined published applicationTokkai 2002-30217 has an adverse effect as a low thermal conductingratio because the electronic component and the heat sink as the heatdissipating member are bonded through thermal conductive resin. Furtherthe disclosed technology in the unexamined published applicationTokkai-Sho 63-102345 is that an electronic component and a heat sink areadhered and connected through metal in a state of semi-coagulation.Accordingly, the technology has such a problem that the metal in thestate of semi-coagulation makes short-circuits in a printed circuitboard or electronic components when the metal flows out and is scatteredaround. More further the disclosed technology in the Patent application2002-140316 results in increases of the number and cost of parts, andsteps of manufacturing because of the bank preventing the flow-out ofthe liquid metal.

SUMMARY OF THE INVENTION

The object of the present invention is to increase a thermalconductivity between an electronic component and a heat dissipatingmember by means of increasing the degree of contact for heat-conductingbetween the heat dissipating member and a heat conducting member. As aresult, an effect of heat dissipation from the electronic part isimproved. Further the present invention provides a new electroniccomponent device which prevents short-circuits in a surrounding printedcircuit board and/or electronic components, and which can be producedwithout increasing the number of parts, cost of parts, and steps ofmanufacturing thereof.

The present invention relates to an electronic component device in whichan electronic component and a heat dissipating member are connectedthrough a heat conducting member. For further details, a metallic memberas a heat conducting member is provided on each of the electroniccomponent and the heat dissipating member respectively, where themetallic member is formed by means of vapor deposition or metal plating.And each of the metallic members is formed into solid solution with aliquid metal and fixed to each other. Accordingly, the electroniccomponent and the heat dissipating member are connected through a heatconducting member as solid solution comprising the metallic members andthe liquid metal. The contact area for heat conduction between theelectronic component and the heat conducting member results in larger.Furthermore a heat conductivity between the metallic member as a heatconducting member and the liquid metal is increased. Since the solidsolution of the metallic member and the liquid metal is formed at a roomtemperature, the electronic components are free of heat stress.

And furthermore the recessed metallic member is integrally formed with abottom part and a bank part, where the bank is projection-like anddisposed at a periphery of the bottom, and the liquid metal is filled inthe recess portion and formed into a solid solution. Therefore theliquid metal is sealed in the recess portion and cannot flow out fromthe recess portion. As a result, the short-circuits in printed circuitsor electronic components around the recessed metallic member can beprevented. Since the recessed metallic member is integrated with thebank and the bottom as a single piece without using a plurality ofparts, a decrease in the number of parts and the suppression of increasein steps are can be achieved.

The metallic member comprises indium (symbol of element: In), and aliquid metal is at least one of Ga, Ga—In alloy (gallium and indiumalloy), Ga—In—Sn alloy (gallium, indium, and tin alloy), Ga—In—Zn alloy(gallium, indium, and zinc alloy), Ga—Sn alloy (gallium and tin alloy),Ga—Zn alloy (gallium and zinc alloy). Therefore the metallic member anda liquid metal which form a heat conducting member coagulate and formsolid solution. The configuration increases the degree of contact forheat conduction and improves a coefficient of thermal conductivity. As aresult, the heat generated in electronic components is effectivelyradiated.

Further, the metal member provided to electronic components or heatdissipating member is formed with metal plating processing or vapordeposition processing. Accordingly, the formation increases the degreeof the contact of heat conduction between an electronic component and aheat conducting member, and increases also the degree of the contactbetween a heat dissipating member and heat conducting member. As aresult, the formation can improve the heat dissipating effect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram of the electronic component device concerningthis invention.

FIG. 2 shows a schematic diagram of a plating unit which manufacturesthe electronic component device concerning an embodiment of theinvention.

FIG. 3 shows a schematic diagram of the electronic components concerningthe embodiment.

FIG. 4 is a schematic diagram of the heat dissipation member concerningthe embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention is explained with respect to thedrawings. FIG. 1 shows the structure of the electronic component device1 of the present invention.

Reference 1 indicates the electronic component device, reference 2indicates an electronic component, such as a semiconductor component,reference 3 indicates a heat dissipating member made of metal havinghigh heat conducting ratio, such as aluminum, reference 4 indicates aheat conducting member, reference 41 indicates a recessed metallicmember, reference 411 indicates a projecting bank section of therecessed metallic member, reference 412 indicates the bottom of therecessed metallic member, reference 42 is a plate shape metallic member,and reference 43 indicates a liquid metal.

In this electronic component device 1, the electronic component 2 andthe heat dissipating member 3 are connected with the heat conductingmember 4. The heat conducting member 4 is formed with the recessedmetallic member 41, the plate shape metallic member 42, and the liquidmetal 43. The recessed metallic member 41 is integrally formed with thebottom 412 and the projecting bank section 411 disposed at theperipheral portion of the recessed metallic member 41. The projectingbank section 411 at the periphery portion and the bottom 412 are formedby plating treatment.

Specifically, the recessed metallic member 41 of the heat conductor 4 isformed in the upper part of the electronic component 2 by plating. Theplate shape metallic member 42 of the heat conductor 4 is formed in thelower part of the dissipating member 3 by plating. And the bottom 412surrounded by the projecting bank section 411 of the recessed metallicmember 41 is filled up with the liquid metal 43. For example, an alloyincluding Ga with high heat conductivity high can be used as a liquidmetal 43. A metal which can mutually form a solid solution with theabove mentioned liquid metal 43 and not decrease the heat conductivitywhen the metal forms a solid solution is preferable as a material forthe recessed metallic member 41 and the plane shape metallic member 42,indium (symbol of element: In) or a alloy including indium is elected asthe material.

This electronic component device 1 is mounted on the circuit board, andworks. The electronic component device 1 produces heat when it isworking. The heat produced by the electronic component 1 is conductedthrough the heat conducting member 4 and then dissipated at the heatdissipating member 3. Accordingly, the electronic component is cooledand kept at a suitable temperature, and works steadily or continually.

A plating unit 10 for manufacturing the electronic component device isexplained in connection with FIG. 2. This plating unit 10 can fillplating liquid in a plating bath 11, and can prepare for plating, forexample, In, using an anode pole 12 and a cathode pole 13, a requiredcurrent being provided between the anode and cathode poles.

Referring to FIG. 3, the manufacturing process for the electroniccomponent is explained.

(1) At first, the electronic component 2 is prepared. And then, theportions not to be plated are masked. For example, resin, as a resist,is applied over such portions. The electronic component 2 is attached tothe hanger of the plating unit 10 after that, and it lays in the platingbath of the plating unit 10.

(2) Next, an acid immersion processing is carried out. As for processingconditions, the acid solution is a sulfuric acid of about 10% ofconcentration, and a temperature of the solution is maintained at roomtemperature, for example, 15° C. And the electronic component 2 is swunggently with the amplitude of about 75 mm in a stroke of about 30 secondswithin a plating bathtub. And after losing the oil film and dirt in theplating treatment area, the electronic component 2 is rinsed forremoving the sulfuric acid solution.

(3) The electronic component 2 is nickel-plated continuously. As forplating conditions, for example, pH of Watts bath is about pH4.5, thecurrent density is 4 A/square dm, and the temperature of the solution isabout 50° C. The electronic component 2 is swung gently with a strokeamplitude of about 75 mm of so as to form an underplate, while theplating solution is being stirred. The electronic component 2 is rinsedto remove the plating solution.

(4) Next, an acid immersion processing is carried out. As for details ofprocessing conditions, the acid solution is Dainsilver (DaiwakaseiKabushikikaisha: trade name ACC) of about 10% of concentration, and thesolution is maintained at room temperature. The electronic component 2is swung gently with the amplitude of about 75 mm of stroke within theplating bathtub for about 30 seconds. And the oil film and dirt in theplating treatment area are removed. Then the electronic component 2 isrinsed for removing the acid solution.

(5) Next, a strike In plating processing is carried out. As for platingprocessing conditions, for example, plating solution is DAININ-PL30(Daiwakasei kabushikikaisha: the chief ingredient is methanesulfonicacid indium), current density is about 7.5 A/square dm, and thetemperature of the acid solution is about 50° C. Strike plating iscarried out while the electronic component 2 is swung gently with astroke amplitude of about 75 mm while the plating solution is beingstirred.

(6) Next, In plating processing is carried out. As for platingprocessing conditions, for example, for plating solution is DAININ-PL30(Daiwakasei Kabushikikaisha: the chief ingredient is methanesulfonicacid indium), current density is about 0.5 A/square dm, and thetemperature of the plating solution is about 50° C. Plating is carriedout while the electronic component 2 is swung gently with a strokeamplitude of about 75 mm and while the plating solution is beingstirred. The thickness of this In plating is about 0.1 mm. The platingwas provided in a plate shape in the area except for the portion of theelectronic component 2 on which the resin, as a resist, was applied.

(7) Next, the resin as a resist is applied on the plate of this plating.The domain on which the resin, as a resist, is applied is a domainexcept for the projecting bank section 411 at the periphery part of theelectronic component 2. The resin, as resist, is PDF100 (trade name)produced by Shinnittetsu-kagaku kabushikikaisha. As for conditions forlaminating, a temperature is about 80° C. and the degree of vacuum isabout 0.3 MPa.

(8) Next, a plating processing is carried out. As for processingconditions, for example, the plating solution is DAININ-PL30 (Trade nameavailable from Daiwakasei Kabushikikaisha: chief ingredient ismethanesulfonic acid indium), the current density is about 0.5 A/squaredm (wherein “dm”=decimeter, or 10 cm), and the temperature of theplating solution is about 50° C. The plating is carried out, while thesolution is stirred by air blowing and the electronic component 2 isswung gently with a stroke amplitude of about 75 mm. The thickness of Inplating is about 0.02 mm. Therefore, the recessed metallic member 41 ofthe heat conduction member 4 has been formed in the electronic component2. The dimensions of the formed shape are: the thickness of the bottomis about 0.1 mm; the internal height of the projecting bank section 411in the recessed metallic member 41 is about 0.02 mm; and the width isabout 5 mm.

Thus, in order for electronic component 2 to have a recessed metallicmember 41 formed by plating processing, the degree of contact for heatconduction is good. And the projecting bank section 411 formed at theperiphery part of the recessed metallic member 41 and the bottom 412 areformed in one plating processing. For this reason, the reduction ofparts and the prevention of increase in a manufacture can be performedwithout preparing another parts.

(9) Next, the resin, as resist, used by the above-mentionedmanufacturing process is removed. If exfoliation liquid is used, it cancarry out the resist easily.

(10) Next, the plate shape metallic member 42 is formed on the heatdissipation member 3. The manufacturing method of the heat dissipationmember 3 is explained with reference to FIG. 4. The plate shape metallicmember 42 is formed by a manufacturing method using the plating artmentioned above. Plating processing is carried out and the heatdissipation member 3 is plated, as mentioned above, to form the plateshape metallic member 42 in the bottom of the heat dissipation member 3as seen in FIG. 4. The degree of contact of the heat conduction of theheat dissipation member 3 and the plate shape metallic member 42 isgood, because of this plating processing.

(11) The liquid metal 43, specifically liquid gallium (symbol ofelement: Ga), is filled up in the portion surrounded by the projectingbank formed in the electronic components 2. A dispenser apparatusperforms a filling method.

(12) The electronic components and the heat dissipation member 3mentioned above are stacked. Therefore, each of the metal members 41, 42and the liquid metal 43 solidifies, and they become a solid solution.The solid solution is formed in a normal temperature for several tens ofhours. For this reason, heat stress is not given to the electroniccomponent. Liquid metal 43 is liquefied until it becomes a solidsolution, but since it is surrounded by the projecting bank section 411,it does not leak to the circumference. If the solid solution iscompleted, the metal members 41, 42 and the liquid metal 43 adhere eachother, and the electronic component device 1 is completed.

Other Embodiments

The above-mentioned embodiment explained the example which uses Ga forliquid metal. However, the same effect is obtained even if a 75.5%Ga-24.5% In alloy, 62% Ga-25% In-13% Sn alloy, 67% Ga-29% In-4% Znalloy, 92% Ga-8% Sn alloy, or 95% Ga-5% Zn alloy is used as the liquidmetal.

In the above-mentioned embodiment, the recessed metallic member 41 isformed on the electronic component 2, and the plate shape metallicmember 42 is formed at the heat dissipation member 3. However, anelectronic component device 1 is mounted in a circuit board in variousstates. According to the state of mounting the electronic componentdevice 1, the plate shape metallic member 42 may be formed on theelectronic component 2, and recessed metal member may be formed in theheat dissipation member 3.

INDUSTRIAL APPLICABILITY

As explained above, the electronic component device provided by thepresent invention increases the degree of contact of the heat conductionof electronic components and a thermally conductive member, andincreases the degree of contact of the heat conduction of a heatdissipation member and a thermally conductive member. As a result, aradiation effect of electronic components can be raised. Further, shortcircuits in a circuit board and electronic components close to theelectronic component device are prevented, and an increase of the numberof parts and steps for manufacturing are suppressed.

1. An electronic device, comprising: an electronic component; a heatdissipating member; and a plate configured to conduct heat, the platebeing formed with a recessed metallic member, a plate-shaped metallicmember, and a solid solution and being disposed between and bonded tosaid electronic component and said heat dissipating member, the solidsolution being composed of gallium and indium.
 2. The electronic deviceaccording to claim 1, wherein the solid solution is secured in therecessed metallic member.
 3. The electronic device according to claim 2,wherein said recessed metallic member is composed of one of indium andan alloy including indium.
 4. The electronic device according to claim1, wherein the plate-shaped metallic member is composed of one of indiumand an alloy including indium.